alt Hacker NewsWhen the calling convention is such that the caller owns the function arguments, the callee can’t remove/replace them on the stack, but has to keep them across the tail call. In turn, it means that the callee has to clean up the arguments to the tail call, and thus can’t actually make a tail call, unless the argument list happens to be identical to the original call.
But the compiler controls both the caller and callee. It doesn't need to respect any calling convention during a TCO. In fact it won't; it'll jump instead of calling.